The use of microwave energy for cooking has been available for many years. However, many foods are considered to be "non-microwaveable foods." Such foods share the characteristic that microwave energy does not evenly heat the food item, or else the microwave energy produces an undesirable food texture. Examples of food typically considered to be non-microwaveable are bread and pizza dough. Bread products are typically non-microwaveable because microwaving of bread products causes a phenomenon known as cross-linking of starches and proteins which leads to cellular breakdown in the starches, and ultimately leads to an undesirable texture. In addition to the undesirable texture found in microwaved bread products, microwave cooking of bread products tends to drive out moisture and heat the bread product in an uneven manner.
It is known in the art to use microwave transparent materials as cooking vessels for use in a microwave oven. It is also known to use microwave shielding material to shield microwave energy from a food product or to focus microwave energy to a particular portion of a food product. It is also known to use microwave susceptor materials in microwave cooking apparatuses for directly heating food and browning by conduction from microwave susceptor material heated by absorption of microwaves.
The self-venting microwaveable package disclosed in U.S. Pat. No. 5,464,969 is a microwaveable plastic bag for heating a variety of products including liquids. One seam of the bag incorporates a strip seal that vents when enough pressure is generated in the bag, to prevent explosion.
An appliance for cooking a frozen pizza pie with microwave energy is disclosed in U.S. Pat. No. 5,247,149. A tray for supporting and cooking a frozen pizza pie is octagonal in shape, and the upper surface of the tray carries a microwave susceptor material. The tray has side tabs which also carry microwave susceptor material and which fold over the edge crust and contact the dough of the frozen pizza.
A multi-layer microwave conductive structure is disclosed in U.S. Pat. No. 5,530,231, which is incorporated herein by reference. A conductive structure for use in microwave food packaging is disclosed that adapts itself to heat food articles in a safer, more uniform manner is disclosed. The structure includes a conductive layer disposed on a non-conductive substrate. Provision in the structure's conductive layer of links and base areas causes microwave induced current to be channeled through the links resulting in controlled heating.
Metallized microwave diffuser films are disclosed in U.S. Pat. No. 5,300,746 which is incorporated herein by reference. The films include an insulative substrate having a first side upon which is deposited a metallic coating capable of selectively reflecting a portion of incoming microwave energy.
Those systems, which disclose vessels for heating or cooking using microwave energy or disclose materials which reflect microwave energy or become hot upon contact with microwave energy transmission, may be used to heat and cook food products adequately, but are ineffective in cooking bread products, such as uncooked pizza dough, which include starch components in the basic structural make-up of the food product. As discussed above, bread products cooked by microwave energy typically exhibit an undesirable texture due to cellular break down of the starch components contained therein.
Therefore, there is a need in the art for a microwave cooking package system which may be used to cook a fresh, frozen, or refrigerated cooked or uncooked dough product in a microwave oven with the resulting bread having the texture and taste of bread cooked in a conventional oven.